In recent years, with the advent of web-based access to voice and video files on the Internet, it has been an obsession with the network engineers to develop an Internet Protocol (IP)-based packet transmission and delivery mechanism that provides end-system to end-system service reliability, while at the same time maintains the service differentiation requirements. Such a mechanism must recover from failures without any perceptible change in the transmission of data packets.
The attempts so far in the packet-switched environment has been less than encouraging. Current technologies do not meet the needs of the rapid failure recovery to the extent that users and network operators want. The providers of services and devices build their systems with enough redundant system components to ensure that during failure of an active system, a redundant system that can take all or part of the load of the active system, gets activated and maintains service continuity. The problem however lies in the fact that the changeover to the redundant system is typically very slow. If there is a route failure in a network today, the routing protocols and the associated hardware failover mechanism can take from a few seconds to a few minutes to provide the redundant route for the traffic. Such delays are not acceptable for time-sensitive traffic, such as voice and video. The delays are also not acceptable in non-time sensitive traffic such as file transfers and important transactions. The delays generally entail hardware and operational complexities not desired in most networks.